Moderate stress will cause an increase in synaptosomal glutamate and choline uptake in the hippocampus, septum, frontal cortex, and basal ganglia of the rat. These increases occur after serum increases in endogenous corticosteroids. Consequently, the role of corticosteroids in modulating this brain change is of interest. Thus far, glutamate and choline uptake were investigated in vitro and in vivo in naive rats. No corticosteroid dependence was noted. Ongoing experiments with adrenalectomized rats continue.